C++ basic_istream::peek()用法及代码示例

std::basic_istream::peek()用于从输入流中读取下一个字符而不提取它。该函数不接受任何参数，仅返回输入字符串中的下一个字符。以下是相同的语法：

头文件：

#include<iostream>

用法:

int peek();

返回值：std::basic_istream::peek()返回输入字符串中的下一个字符。

下面的程序可以更好地了解std::basic_istream::peek()的实现：

程序1:

// C++ code for std::basic_istream::peek() 
#include <bits/stdc++.h> 
using namespace std; 
  
// main method 
int main() 
{ 
    istringstream gfg("GeeksforGeeks"); 
  
    char c1 = gfg.peek(); 
    char c2 = gfg.get(); 
    char c3 = gfg.get(); 
  
    cout << "The first character is:"
         << c1 << endl 
         << " and the next is:"
         << c3 << endl; 
}

输出：

The first character is:G 
and the next is:e

程序2:

// C++ code for std::basic_istream::peek() 
#include <bits/stdc++.h> 
using namespace std; 
  
// main method 
int main() 
{ 
    istringstream gfg("Computer"); 
  
    char c1 = gfg.peek(); 
    char c2 = gfg.get(); 
    char c3 = gfg.get(); 
  
    cout << "The first character is:"
         << c1 << endl 
         << " and the next is:"
         << c3 << endl; 
}

输出：

The first character is:C 
and the next is:o

程序3:

// C++ code for std::basic_istream::peek() 
#include <bits/stdc++.h> 
using namespace std; 
  
// main method 
int main() 
{ 
    istringstream gfg("Laptop"); 
  
    char c1 = gfg.peek(); 
    char c2 = gfg.get(); 
    char c3 = gfg.get(); 
    char c4 = gfg.get(); 
  
    cout << "The first character is:"
         << c1 << endl 
         << " and the next is:"
         << c3 << endl 
         << " after that next is:"
         << c4 << endl; 
}

输出：

The first character is:L 
and the next is:a 
after that next is:p

参考：http://www.cplusplus.com/reference/istream/basic_istream/peek/

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注：本文由纯净天空筛选整理自bansal_rtk_大神的英文原创作品 basic_istream::peek() in C++ with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。